 default namespace = "http://eric.van-der-vlist.com/ns/library"
 namespace hr = "http://eric.van-der-vlist.com/ns/person"
 
 element library
 {
    element book
    {
       attribute id { text },
       attribute available { text },
       element isbn { text },
       element title { attribute xml:lang { text }, text },
       element hr:author
       {
          attribute id { text },
          element hr:name { text },
          element hr:born { text },
          element hr:dead { text }?
       }*,
       element character
       {
          attribute id { text },
          element hr:name { text },
          element hr:born { text },
          element qualification { text }
       }*
    }+
 }
